Category 4 cable
It is used in telephone networks which can transmit voice and data up to 16 Mbit/s.
For a brief period it was used for some token ring, 10BASE-T, and 100BASE-T4 networks, but was quickly superseded by Category 5 cable. It is no longer common or used in new installations. Category 4 cable is not recognized by the current version of the TIA/EIA-568 data cabling standards.